fatty-alcohol
Fatty Alcohol
Most fatty alcohols are used as derivatives such as poly(oxyethylene) ethers, the corresponding sulfated ethers, and alkyl sulfates, and as esters with phosphoric acid and mono- and dicarboxylic acids.
From: Fatty Acids, 2017
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Stearyl Alcohol Oleogels
Fabio Valoppi, ... Alejandro G. Marangoni, in Edible Oleogels (Second Edition), 2018
Fatty Alcohol-Containing Oleogels Toxicological and Nutritional Considerations
Fatty alcohol-containing oleogels have been shown to be good candidates for the substitution of saturated fats. Since they are intended for consumption, some toxicological and nutritional studies are still needed. All fatty alcohols are biodegradable materials with practically no acute toxicity (e.g., LD50 after oral intake of C18OH in rats >5000 mg/kg), they are mainly oxidized to the respective fatty acids and then integrated into the fatty acid metabolism, while a small part is excreted in conjunction with glucuronic acid (Noweck and Grafahrend, 2000). As previously mentioned, presently C18OH is the only fatty alcohol that has been registered as self-affirmed GRAS ingredient for oleogelation. Due to these considerations, fatty alcohols can be considered edible materials that can be used as oleogelators. However, toxicological tests on fatty alcohol-containing oleogels as well as long-term consumption studies are needed to evaluate their effect on the human metabolism.
The Role of Fatty Acids in Cosmetic Technology
Gary R. Kelm, Randall R. Wickett, in Fatty Acids, 2017
12.4.1 Fatty Alcohols
Fatty alcohols are similar to fatty acids in exhibiting amphiphilic properties and in the chemical and physical properties of the hydrophobic portion of the molecule, but with a nonionizable polar group. Fatty alcohols may be produced directly through hydrogenation of fatty acids. However, the more common route of synthesis is through hydrogenation of methyl esters of fatty acids. The latter are directly produced from natural triacylglycerides (the source of fatty acids) through transesterification with methanol (methanolysis) (Pel, 2001). Fatty alcohols are used extensively in cosmetic and personal care products in emulsion stabilization and also in providing structure for anhydrous sticks and suspensions.
Biochemistry of Lipids, Lipoproteins and Membranes
Fred Snyder, in New Comprehensive Biochemistry, 1996
8.1 Ether lipid precursors
8.1.1 Fatty alcohols
Fatty alcohols are oxidized to fatty acids via an NAD+: fatty alcohol oxidoreductase, a microsomal enzyme found in most mammalian cells (Fig. 3B). The high activity of this enzyme probably accounts for the extremely low levels of unesterified fatty alcohols generally found in tissues or blood. Detection of fatty aldehydes, by trapping them as semicarbazide derivatives during oxidation of the alcohol, suggests that the fatty alcohol oxidoreductase catalyzes a two-step reaction that involves an aldehyde intermediate.
8.1.2 Dihydroxyacetone-P and acyldihydroxyacetone-P
Dihydroxyacetone-P can be diverted from its precursor role in ether lipid synthesis when it is converted to sn-glycerol-3-P by NADH:glycerol-3-P dehydrogenase. Another bypass that prevents the formation of alkyldihydroxyacetone-P occurs if the ketone function of acyldihydroxyacetone-P is first reduced by an NADPH-dependent oxidoreductase, since the product, 1-acyl-2-lyso-sn-glycerol-3-P, can then be converted to different diacyl types of glycerolipids. Obviously, the metabolic removal and/or formation of fatty alcohols, dihydroxyacetone-P, or acyldihydroxyacetone-P from the ether lipid precursor pool represent important control points for regulating the ether lipid pathway.
Sjögren–Larsson Syndrome
J.-B. Roullet, W.B. Rizzo, in Encyclopedia of the Neurological Sciences (Second Edition), 2014
Fatty alcohol accumulation
Fatty alcohols such as hexadecanol (C16:0) and octadecanol (C18:0) accumulate in SLS patients due to FALDH/FAO deficiency. These alcohols have a high propensity to partition into membranes and are expected to accumulate in myelin. Saturated alcohols less than 14 carbons long interfere with nerve transmission and have anesthetic properties, but alcohols longer than 14 carbons are virtually devoid of this effect. In-vitro studies indicate that long-chain alcohols become incorporated into synaptic vesicles. Medium- and long-chain alcohols up to 12 carbons long potentiate γ-aminobutyric acid type A (GABAA) receptor function and interfere with the righting reflex in mice. With respect to SLS, the effects of longer-chain C16–C18 alcohols on GABAA receptor function are not known.
Shampoo Formulation
Ken Klein, Irwin Palefsky, in Handbook for Cleaning/Decontamination of Surfaces, 2007
1.1. Sulfates
Fatty alcohol sulfates clearly predominate in the anionic category. They can be made by reacting a fatty alcohol with chlorosulfonic acid (CSA) which is then neutralized with an appropriate base (ammonium hydroxide, sodium hydroxide, magnesium hydroxide or triethanolamine) to form the fatty alcohol sulfate. When this manufacturing route is taken, there is a significant amount of residual salt, which can play a major role in building viscosity.
ROH+CISO3H ⇒ ROSO3− H+ + HCl
ROSO3− H+ + NaOH ⇒ ROSO3−Na+ (sodium lauryl sulfate)
Another process employs sulfur trioxide in place of CSA. Since no salt is formed in this process, the manufacturers will post add it to the completed product. Other by-products include unsulfated alcohol and sodium sulfate. These too will affect the performance of the commercial surfactant. Of major importance is the nature of the starting fatty alcohol. It is well known that as we increase the chain length (number of carbon atoms), the irritation potential of the resultant surfactant decreases while the ability to build viscosity increases. Additionally, the cloud point is lowered while the solubility is decreased. Note the relationship between solubility and viscosity building; they vary inversely. This is seen constantly with surfactants of all classes. It is also the mechanism by which alkanolamides affect the viscosity by shifting the position of the salt curve. Additionally, the foam decreases quite rapidly as the chain length increases. It was discovered quite some time ago that the best compromise considering foam, viscosity and irritation was 12 carbons. Thus, we see that lauryl sulfates predominate. The longer chain length sulfates (cetearyl, C16–18) can be used as emulsifiers or in opaque cream shampoos. Generally speaking, the alcohols used are straight chain materials derived from coco or synthetic sources. Another factor to be considered when using fatty alcohol sulfates is ethoxylation. By starting with an ethoxylated alcohol, we can produce fatty alcohol ether sulfates. Generally these surfactants are less irritating than their unethoxylated counterparts due to several factors including a dilution of the percentage that the sulfate moiety occupies in the molecule. Additionally, since the ethylene oxide increases the polarity, and thus solubility of the surfactant they are more difficult to build in viscosity but their cloud points are lower. The foam that is produced by these surfactants is less dense but quite acceptable as long as the number of moles of ethylene oxide (EO) is three or less. A final word about fatty alcohol sulfates (and ether sulfates) relates to the neutralizer. About ten years ago, the sodium adducts were by far the most popular, but this has changed. Now the ammonium-neutralized sulfates are quite popular and are seen in everyday conditioning and anti-dandruff shampoos. These surfactants should be used at a pH of less than 6.5. A higher pH will result in the liberation of ammonia, which is most unpleasant, and not very consumer friendly. The sodium alkyl sulfates should be used at a pH above 5.0, since some hydrolysis may occur at lower pHs. The triethanolamine alkyl sulfates are not used as often as the sodium or ammonium materials due to poorer viscosity (better solubility) building and poorer foam density along with the potential for color degradation at high temperatures.
Olive-oil quality biotechnologies
Zeev Wiesman, in Desert Olive Oil Cultivation, 2009
Waxes
Waxes are esters of fatty alcohols and fatty acids. The refining process can eliminate aliphatic alcohols, but it is more difficult to remove waxes. Olive-pomace oil contains more waxes than virgin olive oil because pomace contains a greater portion of fruit skin, which is where most of the waxes originate; because of this difference, the wax content is used to identify adulteration with pomace oil.
The presence of wax in olive oil can be determined by gas chromatography. The main waxes found are the esters C-36, C-38, C-42, C-44 and C-46 (Kiritsakis, 1998). There is an international standard for virgin olive oils, refined olive oils, olive oils, refined olive-pomace oils and olive-pomace oils, fixed at ≤ 250, ≤ 350, ≤ 350, > 350, and > 350 mg/kg, respectively (IOC, 2006).
Polymers for a Sustainable Environment and Green Energy
C.D. Neveu, ... N.J. Iroff, in Polymer Science: A Comprehensive Reference, 2012
10.26.1.2.2 Transesterification
In transesterification, the fatty alcohol is reacted with a lower alkyl methacrylate ester to form the higher alkyl methacrylate ester and the lower carbon chain alcohol. MMA is typically used as methacrylate ester and methanol is formed as a by-product as shown in Figure 4. The reaction is reversible and is driven to high conversion by removing methanol as an azeotrope with MMA via distillation. The use of a packed column is required for this distillation to maximize the concentration of methanol in the distillate.
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Figure 4. Transesterification chemistry.
A variety of compounds are used to catalyze methacrylate transesterifications, including metal salts of lithium, aluminum, titanium, zirconium, tin, and lead. Key to the selection of an appropriate catalyst is reactivity, selectivity, and catalyst removal. Alkoxy titanates, lithium hydroxide, and tin oxides are commonly used commercial catalysts for methacrylate transesterification reactions.
Typical polymerization inhibitors such as HQ or MEHQ are added to the reaction mixture to prevent polymerization during the reaction and subsequent purification steps. The reaction is typically run with excess MMA. At the end of the reaction, the MMA is stripped at reduced pressure and the catalyst is removed either by filtration or by hydrolysis and filtration.
Nutrient Profiles of Commercial Table Olives
Antonio López-López, ... Antonio Garrido-Fernández, in Olives and Olive Oil in Health and Disease Prevention, 2010
75.4.3 Content of Fatty and Triterpenic Alcohols
The mean concentration of total alcohols (fatty and triterpenic alcohols) was 13.3 mg 100 g−1 e.p. with a minimum of 6.49 mg 100 g−1 e.p. in Gordal olive ‘salads’, and maximum 41.80 mg 100 g−1 e.p. in seasoned Arbequina turning-color olives. The most abundant are octacosanol, hexacosanol, and erythrodiol, with global averages of 4.7, 3.5, and 2.6 mg 100 g−1 e.p., respectively. Levels of triterpenic dialcohols are higher in olive-pomace oils (extracted from olive pomace with solvents) than in virgin and refined olive oils (Cañabate-Díaz et al., 2007). The alcohols in table olives, expressed as mg 100 g−1 total lipid, are always in higher concentrations than in virgin olive oil but lower than in pomace olive oil.
The overall fatty alcohols are always below 10 mg 100 g−1 e.p. in green and ripe olives while they reach values from 12.9 to 36 mg 100 g−1 e.p. in directly brined olives except in Verdial with 9.2 mg 100 g−1 e.p. (Table 75.5).
Triterpenic alcohol concentrations in table olives are markedly lower than fatty alcohols. In green and ripe olives, the level is always equal to or below 5.54 mg 100 g−1 e.p. but is higher in many commercial presentations of directly brined olives, with the highest content found in the Verdial cultivar (11.59 g 100 g−1 e.p.) (Table 75.5).
Detailed information on the fatty and triterpenic alcohol levels in table olives can be found elsewhere (López-López et al., 2008).
Lepidoptera: Female sex pheromone biosynthesis and its hormonal regulation
R.A. Jurenka, in Insect Pheromone Biochemistry and Molecular Biology (Second Edition), 2021
2.3.5.1 Fatty alcohol oxidase
The oxidation or dehydrogenation of fatty alcohols will produce an aldehyde (Rizzo, 2014). This enzyme has been characterized from pheromone glands of H.zea and M. sexta by applying various alcohols to intact or excised pheromone glands (Fang et al., 1995b; Hoskovec et al., 2002; Luxova and Svatos, 2006; Teal and Tumlinson, 1988). Substrate specificity studies conducted with H. zea and M. sexta indicates that a variety of alcohols can be oxidized. The enzyme will also oxidase primary alcohols that are not found in the pheromone gland including benzylalcohol (Luxova and Svatos, 2006). The oxidase was also shown to have a broad substrate acceptance in the fall webworm, Hyphantria cunea (Kiyota et al., 2011). The enzyme is connected to the cuticle and is also active in hexane but not other organic solvents (Teal and Tumlinson, 1988). It seems that the pgFAR will produce species-specific fatty alcohols and then the oxidase will convert them to the aldehyde for release. Location of aldehydes and alcohols in pheromone glands of H. virescens indicates that the alcohols are located inside the gland beneath the cuticle but the aldehydes are found primarily on the outside cuticle of the gland (Foster and Anderson, 2019). The gene encoding the oxidase enzyme that produces aldehydes has not been identified at the molecular level and transcriptome studies have not been informative in helping to identify the enzyme. In those insects that utilize both an alcohol and an aldehyde as part of their pheromone, it is unclear how the production of both components would be produced in specific ratios.
Formulations and challenges: a special emphasis on stability and safety evaluations
Surashree Sen Gupta, Mahua Ghosh, in Developing New Functional Food and Nutraceutical Products, 2017
8.3.2 High melting point of nutraceuticals
Compounds such as phytosterols, fatty alcohols, and carotenoids are crystalline at normal room temperature. This makes it an arduous job to incorporate such products into foods especially at room temperature. If forcibly they are introduced in foods, the stability and shelf life of such food items are markedly deteriorated, resulting in disagreeable appearance and obnoxious odor and mouthfeel, thus in effect affecting the market value and consumer demand of such food items. Additionally, such food items also have lower bioavailability, further limiting their utility.
In such cases, generally the nutraceuticals are dissolved in suitable edible-grade solvents to transform them to a liquid phase. They are then incorporated in foods. They may also be introduced as suspended nanocrystals in the respective food item in a manner that does not hamper their shelf life or affect their appearance and quality (McClements, 2012).
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